Building automation systems encompass a wide variety of systems that aid in the monitoring and control of various aspects of building operation. Building automation systems include security systems, fire safety systems, lighting systems, and HVAC systems. The elements of a building automation system are widely dispersed throughout a facility. For example, an HVAC system may include temperature sensors and ventilation damper controls, as well as other elements that are located in virtually every area of a facility. These building automation systems typically have one or more centralized control stations from which system data may be monitored and various aspects of system operation may be controlled and/or monitored.
To allow for monitoring and control of the dispersed control system elements, building automation systems often employ multi-level communication networks to communicate operational and/or alarm information between operating elements, such as sensors and actuators, and the centralized control station. Further, maintenance, auditing, and other activities often require access to on-site systems by occasional users that require credentials with limited access to specific sites or devices. In an “Internet of things” environment, various devices within the building automation systems, or in other contexts, may be directly-accessible for maintenance, diagnostic, and other purposes. Specific devices, in particular, may need to be accessed but may not include robust authentication and network capabilities.